The present application generally relates to systems and methods for equalizing a laser drive signal in an optical communication system.
There is an ongoing demand for high data rate communications. However, high data rate communications require a wide bandwidth, which can be difficult and expensive to obtain. For example, when communicating high data rates with a laser, there is an increasing loss of signal at high frequencies which limits the available bandwidth.
The main bandwidth limiting element in a laser is the parasitic inductance of the wire-bonds in the laser. One technique to address the parasitic inductance problem and increase the bandwidth is to add a series resistor near the laser to control the current to the laser. However, the addition of the resistor only provides an incremental increase in the bandwidth. Another technique that may be used to increase bandwidth is to incorporate a finite impulse response (FIR) filter into the driver circuit for the laser. The FIR filter is a type of digital signal processor (DSP) filter that has multiple digital taps and a D/A converter. The DSP implementation of an FIR filter generally is impractical to implement at high data rates.